In frame-based bit stream formats the data required for decoding a current frame are usually stored within the data section for that frame.
An exception is the MPEG1 Audio Layer III bit stream with its bit reservoir technique, where data for a current frame is stored in previous frames. The position of the data is indicated in the bit stream by a pointer to the position in byte of the beginning of the main-data in the previous frame. If the decoder did not receive the required previous frame, decoding of the current mp3 frame is skipped.